1. Field of Invention
The invention relates to an antenna, and more particularly to a dipole antenna with an effectively reduced dimension.
2. Related Art
The rapidly developed radio transmission has brought various products and technologies applied in the field of multi-band transmission, such that many new products have the performance of radio transmission to meet the consumer's requirement. The antenna is an important element for transmitting and receiving electromagnetic wave energy in the radio transmission system. If the antenna is lost, the radio transmission system cannot transmit and receive data. Thus, the antenna plays an indispensable role in the radio transmission system. Selecting a proper antenna can match the feature of the product, enhance the transmission property, and further reduce the product cost. Different methods and different materials for manufacturing the antennas are used in different application products. In addition, considerations have to be taken when the antenna is designed according to different frequency bands used in different countries. The commonly used specifications of frequency band include IEEE 802.11, the most popular bluetooth communication (IEEE 802.15.1), and the like. The bluetooth works at the frequency band of 2.4 GHz. IEEE 802.11 is further divided into 802.11a, 802.11b and 802.11g, wherein the 802.11a specification corresponds to the frequency band of 5 GHz, and the 802.11b and 802.11g specifications correspond to the frequency band of 2.4 GHz.
The most-frequently used antennas in the industry include a monopole antenna, an inverted-F antenna, and a dipole antenna. Because the dipole antenna can effectively radiate and receive the electromagnetic wave, it is widely used in various communication fields. However, if the conventional dipole antenna wants to reach the better polarization effect, its dimension cannot be effectively reduced, and the product dimension has to be increased and cannot meet the miniaturization trend of the current electrical device.
Therefore, it is an important subject of the invention to design a dipole antenna with an effectively reduced dimension such that the product can be minimized.